2008 DRAFT MANURE GAAMPS

Transcription

1 2008 DRAFT MANURE GAAMPS In the event of an agricultural pollution emergency, such as a chemical/fertilizer spill, manure lagoon breach, etc., the Michigan Department of Agriculture and/or the Michigan Department of Environmental Quality should be contacted at the following emergency telephone numbers: Michigan Department of Agriculture: (800) Michigan Department of Environmental Quality: (800) If there is not an emergency, but you have questions on the Michigan Right to Farm Act or items concerning a farm operation, please contact the: Michigan Department of Agriculture Right to Farm Program P.O. Box Lansing, Michigan (517) (517) FAX (877) (Toll Free) Authority: Act 93 of 1981, as amended TOTAL NUMBER OF COPIES PRINTED: 300 TOTAL COST: $ COST PER COPY: $2.68

2 TABLE OF CONTENTS PREFACE...iii I. - INTRODUCTION... 1 About This Document... 1 Quick Reference to the GAAMPs for Manure Management and Utilization... 3 II. CONTAMINATED RUNOFF CONTROL AND WASTEWATER MANAGEMENT... 8 Storage Basins for Runoff Control... 8 Land Application of Runoff... 8 Infiltration Areas... 9 Pasture Systems... 9 Outside Lots III. - ODOR MANAGEMENT Feed Materials Manure Stacked Solid Manure Outside Lots Storages and Acceptable Covers Treatment Systems Lagoons and Storage Basins Composting Methane Digesters Application of Manure to Land IV. - CONSTRUCTION DESIGN AND MANAGEMENT FOR MANURE STORAGE AND TREATMENT FACILITIES Construction Design Seepage Control for Earthen Basins Management V. - MANURE APPLICATION TO LAND Soil Fertility Testing Fertilizer Recommendations Manure Analysis Manure Nutrient Loadings Manure Nutrient Loadings on Pasture Land Method of Manure Application Timing of Manure Application Management of Manure Applications to Land VI. - APPENDICES Appendix A - Tables Appendix B - Manure and Nutrient Management Plans Appendix C - Sample MMSP REFERENCES... 46

3 PREFACE The Michigan legislature passed into law the Michigan Right to Farm Act (Act 93 of 1981, as amended), which requires the establishment of Generally Accepted Agricultural and Management Practices (GAAMPs). These practices are written to provide uniform, statewide standards and acceptable management practices based on sound science. These practices can serve producers in the various sectors of the industry to compare or improve their own managerial routines. New scientific discoveries and changing economic conditions may require necessary revision of the GAAMPs. The GAAMPs that have been developed are the following: 1) 1988 Manure Management and Utilization 2) 1991 Pesticide Utilization and Pest Control 3) 1993 Nutrient Utilization 4) 1995 Care of Farm Animals 5) 1996 Cranberry Production 6) 2000 Site Selection and Odor Control for New and Expanding Livestock Production Facilities 7) 2003 Irrigation Water Use These GAAMPs were developed with industry, university, and multi-governmental agency input. As agricultural operations continue to change, new practices may be developed to address the concerns of the neighboring community. Agricultural producers who voluntarily follow these practices are provided protection from public or private nuisance litigation under the Right to Farm Act. The MDA website for the GAAMPs is at to access. iii

4 I. - INTRODUCTION Like all other segments of our economy, agriculture has changed significantly during the past fifty years and will continue to change in the future. The trend toward larger facilities (the overwhelming majority being family owned and operated) has resulted in farm operations being more capital intensive and less labor intensive. Larger farm size offers marketing advantages and generally lower unit cost of production compared to smaller sized operations. However, increased farm size brings new management challenges for environmental protection, animal welfare, and human welfare. Animal agriculture in Michigan must have the flexibility and opportunity to change agricultural enterprises and to adopt new technology to remain economically viable and competitive in the market place while being protective of the environment. If a healthy, growing livestock industry in Michigan is to be assured, efforts must continue to address the concerns of livestock producers and their neighbors, particularly in two areas: (1) producers who use GAAMPs in the livestock operations should be protected from harassment and nuisance complaints and (2) persons living near livestock operations which do not follow GAAMPs, need to have concerns addressed when odor nuisance or water quality problems occur. No two livestock operations in Michigan can be expected to be the same, due to the large number of variables, which together determine the nature of a particular operation. The GAAMPs presented in this document provide options to assist with the development of environmental practices for a particular farm that prevents surface water and groundwater pollution. These GAAMPs are referenced in Michigan's Natural Resources and Environmental Protection Act (NREPA), Act 451 of 1994, as amended. NREPA protects the waters of the state from the release of pollutants in quantities and/or concentrations that violate established water quality standards. In addition, the GAAMPs utilize the nationally recognized construction and management standard to provide runoff control for a 25 year, 24 hour rainfall event. Air quality issues related to production agriculture are addressed in the Odor Management Section. About This Document For quick reference, management practices are first presented as a numbered list. This list is not meant to convey all the information regarding GAAMPs. Rather, it is intended to be a useful tool to assist individuals in determining what management practices exist and in what section of this document further information can be found. The remainder of the document provides additional information on each of these management practices and is categorized in four areas: 1) runoff control and wastewater management, 2) odor management, 3) construction design and management for 1

5 manure storage and treatment facilities, and 4) manure application to land. Throughout this document you will find some text that is bolded and other text that is not. Section headings and recommended management practices in the GAAMPs for Manure Management and Utilization are in bold text. The un-bolded text provides supplemental information to help clarify the intent of the recommended management practices. Appendix A provides essential data for manure management system planning. Appendix B discusses the difference between Manure Management System Plans (MMSP) and Comprehensive Nutrient Management Plans (CNMP) and explains who needs a CNMP. Appendix C shows a sample MMSP to help the reader become more familiar with the type of information that is typically included in a MMSP. The final portion of this document is a list of references that can provide detailed information not supplied in this document. 2

6 Quick Reference to the GAAMPs for Manure Management and Utilization II. Contaminated Runoff Control and Wastewater Management 1. Facilities may be paved, partially paved around waterers and feed bunks, or unpaved. 2. Runoff control is required for any facility if runoff from the lot leaves the owner's own property or adversely impacts surface and/or groundwater quality. Examples include runoff to a neighbor's land, a roadside ditch, a drain ditch, stream, lake, or wetland. 3. Milk parlor and milk house wastewater shall be managed in a manner to prevent pollution to waters of the state. 4. Provisions should be made to control and/or treat leachate and runoff from stored manure, silage, food processing by-products, or other stored livestock feeds to protect groundwater and surface waters. 5. Runoff storage basins should be designed to contain normally occurring direct precipitation and resulting runoff and manure that accumulate during the storage times projected in the Manure Management System Plan. In addition, storage volume should be provided that will contain the direct rainfall and runoff that occur as a result of the average 25 year, 24 hour rainfall event for the area. Storage basins must be constructed to reduce seepage loss to acceptable levels. 6. Application rates should be determined based upon the ability of the soil to accept and store the water and the ability of plants growing in the application area to utilize nutrients. Land application should be done when the water can be used beneficially by a growing crop. 7. An alternative to a storage pond is a structure for settling solids and an infiltration area wastewater treatment strip (FOTG 635) for handling lot runoff, and/or silage leachate wastewater. The vegetative area may be either a long, grassed, slightly sloping channel or a broad, flat area with little or no slope surrounded by a berm or dike. All outside surface water should be excluded from the infiltration area so that the only water applied is lot runoff and/or silage leachate and direct precipitation. Vegetation should be maintained and harvested at least once per year to prevent excessive nutrient build up in the soil of the infiltration area. 8. Stocking densities and management systems should be employed which ensure that desirable forage species are present with an intensity of stand sufficient to slow the movement of runoff water and control soil erosion and movement of manure nutrients from the pasture land. See the NRCS-FOTG for criteria. 3

7 9. Livestock should be excluded from actual contact with streams or water courses except for controlled crossings and accesses for water or in accordance with the NRCS Prescribed Grazing Standard (NRCS-FOTG). 10. Runoff from pasture feeding and watering areas should travel through a vegetated filter area to protect surface and groundwater. See the NRCS-FOTG for criteria. 11. Provisions should be made to collect, store, utilize, and/or treat manure accumulations and contaminated runoff from outside open lots used for raising livestock. III. Odor Management 12. Livestock producers should plan, design, construct and manage their operations in a manner that minimizes odor impacts upon neighbors. 13. The odor of fermented feed materials, such as corn or hay silage, can be minimized by harvesting and storing them at an appropriate dry matter content (generally greater than 33 percent dry matter). 14. Frequent (daily or every few days) removal of manure from animal space, coupled with storage or stacking and followed by application to cropland at agronomic rates, is an acceptable practice throughout Michigan. 15. Solid manure that may contain bedding materials and/or is dried sufficiently, such as that from poultry, cattle, sheep, swine, horse and fur-bearing animal facilities can be temporarily stacked outside the livestock building. 16. New outside lot systems should not be located in close proximity to residences and other odor-sensitive land uses. They should not be located uphill along a confining valley leading toward residences. New residences or other sensitive land uses should not be located within close proximity to existing outside lot facilities. (For additional guidance, see the GAAMPs for Site Selection and Odor Control for New and Expanding Livestock Production Facilities). 17. Use covered manure storage if technically and economically feasible. 18. Where possible, do not locate manure storage in close proximity to residential areas. 19. Avoid spreading when the wind is blowing toward populated areas. 20. Avoid spreading on weekends/holidays when people are likely to be engaged in nearby outdoor and recreational activities. 4

8 21. Spread in the morning when air begins to warm and is rising, rather than in late afternoon. 22. Use available weather information to best advantage. Turbulent breezes will dissipate and dilute odors, while hot and humid weather tends to concentrate and intensify odors, particularly in the absence of breezes. 23. Take advantage of natural vegetation barriers, such as woodlots or windbreaks, to help filter and dissipate odors. 24. Establish vegetated air filters by planting conifers and shrubs as windbreaks and visual screens between cropland and residential developments. 25. Incorporate manure into soil during, or as soon as possible after, application. This can be done by (a) soil injection or (b) incorporation within 48 hours after a surface application when weather conditions permit. However, incorporation may not be feasible where manures are applied to pastures or forage crops, such as alfalfa, wheat stubble, etc., or where no-till practices are used (see Section V). IV. Construction Design and Management for Manure Storage and Treatment Facilities 26. Construction design for manure storage and treatment facilities should meet specifications and guidelines found in the NRCS-FOTG. Additional publications that can be used are the Concrete Manure Storages Handbook MWPS-36 (MidWest Plan Service, 1994) and Circular Concrete Manure Tanks publication TR-9 (MidWest Plan Service, 1998). 27. To protect groundwater from possible contamination, utilize liners that meet specifications and guidelines in the NRCS-FOTG. Liners include natural existing soil (Barrington and Jutras, 1985; Barrington et al., 1987a, 1987b), bentonite or similar high swell clay materials, compacted earthen liners, and flexible membranes. 28. All manure storage structures shall maintain a minimum freeboard of twelve inches (six inches for fabricated structures) plus the additional storage volume necessary to contain the precipitation and runoff from a 25-year, 24-hour storm event. 5

9 V. Manure Application to Land 29. All fields should be sampled at least every three years, and the soils tested to determine where manure nutrients can best be utilized. 29. All fields used for the production of agricultural crops should have soils sampled and tested on a regular basis to determine where manure nutrients can best be utilized. 30. Use fertilizer recommendations, consistent with those of Michigan State University, to determine the total nutrient needs for crops to be grown on each field that could have manure applied. 31. To determine the nutrient content of manure, analyze it for percent dry matter (solids), ammonium N (NH 4 -N), and total N, P, and K. 32. The agronomic (fertilizer) rate of N recommended for crops (consistent with Michigan State University N fertilizer recommendations) should not be exceeded by the amount of available N added, either by manure applied, by manure plus fertilizer N applied, and/or by other N sources. For legume crops, the removal value of N may be used as the maximum N rate for manure applications. The available N per ton or per 1000 gallons of manure should be determined by using a manure analysis and the appropriate mineralization factors (see Manure Management Sheet #2, MSUE Bulletin E-2344 by Jacobs et al., 1992b) for organic N released during the first growing season following application and the three succeeding growing seasons. 33. If the Bray P1 soil test level for P reaches 150 lb/acre (75ppm), manure applications should be reduced to a rate where manure P added does not exceed the P removed by the harvested crop. (If this manure rate is impractical due to manure spreading equipment or crop production management, a quantity of manure P equal to the amount of P removed by up to four crop years can be used for the first crop year, if no additional fertilizer or manure P is applied for the remaining crop years, and this rate does not exceed the N fertilizer recommendations for the first crop grown.) If the Bray P1 soil test reaches 300 lb/acre (150ppm) or higher, manure applications should be discontinued until nutrient harvest by crops reduces P test levels to less than 300 lb/acre (150ppm). To protect surface water quality against discharges of P, adequate soil and water conservation practices should be used to control runoff and erosion from fields where manure is applied. 34. Manures should be uniformly applied to soils. The amount of manure applied per acre (gallons/acre or tons/acre) should be known, so manure nutrients can be effectively managed. 6

10 35. Manures should not be applied to soils within 150 feet of surface waters or to areas subject to flooding unless: (a) manures are injected or surface-applied with immediate incorporation (i.e., within 48 hours after application) and/or (b) conservation practices are used to protect against runoff and erosion losses to surface waters. 36. Liquid manure applications should be managed in a manner to optimize nutrient utilization and not result in ponding, soil erosion losses, or manure runoff to adjacent property, drainage ditches or surface water. An application that results in manure flow in a field tile line is an unacceptable practice. 37. As land slopes increase from zero percent, the risk of runoff and erosion also increases, particularly for liquid manure. Adequate soil and water conservation practices should be used which will control runoff and erosion for a particular site, taking into consideration such factors as type of manure, bedding material used, surface residue or vegetative conditions, soil type, slope, etc. 38. Where application of manure is necessary in the fall rather than spring or summer, using as many of the following practices as possible will help to minimize potential loss of NO 3 -N by leaching: (a) apply to medium or fine rather than to coarse textured soils; (b) delay applications until soil temperatures fall below 50 F; and/or (c) establish cover crops before or after manure application to help remove NO 3 -N by plant uptake. 39. Application of manure to frozen or snow-covered soils should be avoided, but where necessary, (a) solid manures should only be applied to areas where slopes are six (6) percent or less and (b) liquid manures should only be applied to soils where slopes are three (3) percent or less. In either situation, provisions must be made to control runoff and erosion with soil and water conservation practices, such as vegetative buffer strips between surface waters and soils where manure is applied. 40. Records should be kept of manure analyses, soil test reports, and rates of manure application for individual fields. 7

11 GENERALLY ACCEPTED AGRICULTURAL AND MANAGEMENT PRACTICES II. CONTAMINATED RUNOFF CONTROL AND WASTEWATER MANAGEMENT Rainfall and snowfall-induced runoff from uncovered livestock facilities requires control to protect neighboring land areas and prevent direct discharge to surface or groundwaters. Livestock facilities, which require runoff control, include all holding areas where livestock density precludes sustaining vegetative growth on the soil surface. 1. Facilities may be paved, partially paved around waterers and feed bunks, or unpaved. 2. Runoff control is required for any facility if runoff from the lot leaves the owner's own property or adversely impacts surface and/or groundwater quality. Examples include runoff to a neighbor's land, a roadside ditch, a drain ditch, stream, lake, or wetland. 3. Milk parlor and milk house wastewater shall be managed in a manner to prevent pollution to waters of the state. 4. Provisions should be made to control and/or treat leachate and runoff from stored manure, silage, food processing by-products, or other stored livestock feeds to protect groundwater and surface waters. The NRCS-FOTG, Chapter 6 of MWPS-18 (MidWest Plan Service, 1993), Guideline for Milking Center Wastewater, Natural Resource, Agriculture, and Engineering Service (NRAES-115 by Wright and Graves, 1998). A. Storage Facilities for Runoff Control Runoff control can be achieved by providing facilities to collect and store the runoff for later application to cropland. 5. Runoff storage facilities should be designed to contain normally occurring direct precipitation and resulting runoff and manure that accumulate during the storage times projected in the Manure Management System Plan. In addition, storage volume should be provided that will contain the direct rainfall and runoff that occur as a result of the average 25 year, 24 hour rainfall event for the area. Storage facilities must be constructed to reduce seepage loss to acceptable levels. B. Land Application of Contaminated Runoff Equipment must be available for land application of stored contaminated runoff wastewater. Land application should be done when the soil is dry enough to accept the water. 8

12 6. Application rates should be determined based upon the ability of the soil to accept and store the contaminated runoff and wastewater and the ability of plants growing in the application area to utilize nutrients. Land application should be done when the wastewater can be used beneficially by a growing crop. On fields testing over 150 ppm (300 lb/acre) soil test Bray P1, there may be instances where on-farm generated wastewater, <1% solids, can be utilized efficiently when applied at rates that supply 75% or less of the annual phosphorus removal for the current crop or next crop to be harvested. In these instances, annual sampling of the applied wastewater should occur, soil tests should show a progressive decline over time, and no other phosphorus should be applied to the crop field from other sources. Sprinkler irrigation methods will provide uniform application of liquid with minimum labor requirements. Directing lot runoff through a structure for settling solids can reduce odor from the liquid storage and application to the land (refer to NRCS-FOTG & MWPS-18). For additional guidance, refer to Section III. - Odor Management Practices. C. Infiltration Areas 7. An alternative to a storage pond is a structure for settling solids and an infiltration area wastewater treatment strip for handling lot runoff, and/or silage leachate wastewater. The vegetative area may be either a long, grassed, slightly sloping channel or a broad, flat area with little or no slope surrounded by a berm or dike. All outside surface water should be excluded from the infiltration area so that the only water applied is lot runoff and/or silage leachate and direct precipitation. Vegetation should be maintained and harvested at least once per year to prevent excessive nutrient build up in the soil of the infiltration area. Design information about infiltration areas, such as sizing, establishment, and maintenance, is available in the NRCS-FOTG (635 Wastewater Treatment Strip), MWPS-18, or the Pork Industry Handbook (MSU Extension Bulletin E-1132 by Vanderholm and Nye, 1987). These systems are not practical for every situation. Additional information is available in MWPS-18. D. Pasture Systems Pasture land is land that is primarily used for the production of forage upon which livestock graze. Pasture land is characterized by a predominance of vegetation consisting of desirable forage species (see Moline et al., 1991; Moline and Plummer, 1991). Sites such as loafing areas, confinement areas, or feedlots which have livestock densities that preclude a predominance of desirable forage species are not considered pasture land. 9

13 8. Stocking densities and management systems should be employed which ensure that desirable forage species are present with an intensity of stand sufficient to slow the movement of runoff water and control soil erosion and movement of manure nutrients from the pasture land. See the NRCS-FOTG for criteria. 9. Livestock should be excluded from actual contact with streams or water courses except for controlled crossings and accesses for water or in accordance with the NRCS Prescribed Grazing Standard (NRCS-FOTG). As authorized by the Riparian Doctrine, producers are entitled to utilize surface waters traversing their property. However, this use is limited to activities, which do not result in water quality degradation. The goal for controlling livestock access to surface waters is to prevent water quality degradation. Livestock impact water quality by the erosion of sediment and nutrients from stream banks and by the direct deposition of manure nutrients, organic matter, and pathogens. Direct deposition is effectively prevented by restricting livestock to controlled access locations. Banks are effectively stabilized by maintaining vegetation or, as in the case of controlled watering accesses and crossings, stream banks and beds may be stabilized with appropriate protective cover, such as concrete, rocks, crushed rock, gravel, or other suitable cover. In addition to addressing environmental and public health aspects, controlling livestock access to surface water and providing alternate drinking water sources may improve herd health by reducing exposure to water and soil-borne pathogens. 10. Runoff from pasture feeding and watering areas should travel through a vegetated filter area to protect surface and groundwater. See the NRCS-FOTG for criteria. E. Outside Lots 11. Provisions should be made to collect, store, utilize, and/or treat manure accumulations and contaminated runoff from outside open lots used for raising livestock. Outside open lots used for raising livestock are areas of animal manure accumulation. Maintenance of open lot systems requires manure handling methods to periodically remove accumulated solid or semisolid manure and control lot runoff. Solid manure is typically transferred from the lot to storage facilities or equipment for application to cropland. The frequency of removal of accumulated manure will depend on the animal density (square feet of lot area per animal), the amount of time the animals spend on the lot, the animal size, and the type of feed system. Clean runoff should be diverted away from the livestock lot area. While paved lots generally result in more runoff than 10

14 unpaved lots, a paved surface improves manure collection and runoff control and minimizes the potential for groundwater contamination. 11

15 III. - ODOR MANAGEMENT The goal for effective odor management is to reduce the frequency, intensity, duration and offensiveness of odors, and to manage the operation in a way that tends to create a positive attitude toward the operation. Because of the subjective nature of human responses to certain odors, recommendations for appropriate technology and management practices are not an exact science. The recommendations in this section represent the best professional judgment available. Odor perception is a subjective response to what people detect, through their sense of smell, in the air they breathe. While there is no scientific evidence that odorous gases that escape from livestock operations are toxic at the concentrations experienced by neighbors, they can become an annoyance or a nuisance. 12. Livestock producers should plan, design, construct and manage their operations in a manner that minimizes odor impacts upon neighbors. The proximity of livestock operations to neighbors and populated areas is usually the most critical factor in determining the level of technology and management needed to minimize odor impacts upon neighbors. Therefore, site selection is an important factor in minimizing odor impacts for and upon neighbors. The more remote the livestock operation, the better the likelihood that odors will not become an annoyance for neighbors; and, therefore, a lower level of technology and management will adequately manage odors at the livestock facility. However, the distance which a livestock operation should be located from neighboring land uses to effectively control odors is not easily established. Additional information and recommendations can be found in the GAAMPs for Site Selection and Odor Control for New and Expanding Livestock Operations. The principles upon which the most common and effective techniques for odor control are based include (a) reducing the formation of odor-causing gases and (b) reducing the release of odorous gases into the atmosphere. The degree to which these principles can be applied to the various odor sources found in livestock operations depends on the level of technology and management that can be utilized. Feed materials and manure are the most common and predominant sources of odor and are discussed in the following subsections. Feed Materials Using fermented feeds, such as corn or hay silage, is an acceptable animal husbandry practice throughout Michigan for dairy and beef cattle, horses, sheep and goats. Some odors associated with the storage and feeding of these materials are normal for these livestock operations. 12

16 13. The odor of fermented feed materials, such as corn or hay silage, can be minimized by harvesting and storing them at an appropriate dry matter content (generally greater than 33 percent dry matter). The practice of feeding food processing by-products; (e.g., cull potatoes, dairy whey, pastry by-products, sugar beet pulp and sweet cornhusks) to livestock is a generally accepted practice. This is especially common where livestock operations exist within close proximity to food processing facilities. Using these materials for livestock feed diverts useful by-products (that can pose a substantial load on local sewage treatment plants and a major problem for food processing plants) from the waste stream and converts them into a valuable resource. Properly handled in a livestock operation, these feeds pose no threat to the environment. These products may require special feed handling systems and may substantially increase or change the manure generated by the animals to which they are fed. Some of these by-products, and the manure produced from their consumption by livestock, can generate unusual and rather offensive and intense odors. In these situations, feed handling and manure management practices should be used to control and minimize the frequency and duration of such odors. Human garbage can only be fed under a permit in Michigan. (See P.A. 173 of 953 as amended). Manure Fresh manure is usually considered to be less odorous than anaerobically decomposing manure. Fresh manure emits ammonia but in general is not accompanied by other products of decomposition, which contribute to odors. 14. Frequent (daily or every few days) removal of manure from animal space, coupled with storage or stacking and followed by application to crop land at agronomic rates, is an acceptable practice throughout Michigan. Manure odors are generally those associated with the anaerobic (in the absence of oxygen) decomposition of organic material by microorganisms. The intensity of odors depends upon the biological reactions that take place within the material, the nature of the excreted material (which is dependent upon the species of animal and its diet), the type of bedding material used, and the surface area of the odor source. Sources of decomposing manure can include stacked solid manure, outside lots when manure is allowed to accumulate, uncovered manure storages, manure treatment systems, and land application areas. Stacked Solid Manure 15. Solid manure that may contain bedding materials and/or is dried sufficiently, such as that from poultry, cattle, sheep, swine, horse, and 13

17 fur-bearing animal facilities, can be temporarily stacked outside the livestock building. Temporary stockpiling of manure at field application sites may be necessary when crop production and field conditions preclude immediate application to cropland. Timely application of stockpiled manure to land at agronomic rates and soil incorporation within 48 hours after application will help to control odors and may have nutrient management crop production benefits. Leachate from solid stacked manure is subject to control as described in Section II, Contaminated Runoff Control and Wastewater Management, Practice No. 4. Odors from such manure storages are minimal, except when disturbed such as during removal for application to land. Livestock operations may utilize a variety of bedding materials as part of their manure management system. The use of straw, hay, sand, sawdust, wood shavings, waste paper, or other suitable materials, either individually or in combination as livestock or poultry bedding, is a common generally accepted practice. Bedding materials should be of an appropriate size to maximize absorptive properties and to prevent blowing and dispersion when subsequently applied to cropland. Waxed paper, aluminum foil and plastics should not be present in bedding material. Outside Lots Outside open lots with or without shelters are acceptable for raising livestock in Michigan. In these systems, manure is deposited over a relatively large surface area per animal (compared to a roofed confinement system for example) and begins to decompose in place. Odor impacts can be mitigated by keeping the lot surface as dry as possible, thus limiting the microbiological activity that generates odors. Providing adequate slopes, orientation that takes advantage of sunlight, diverting up-slope runoff water away from the lot, and using recommended stocking densities will enhance drying of the lot surface. The MWPS-18, National Pork Industry Handbook, and Michigan Beef Production Notebook provide details and alternatives to accomplish this. Most feed additives and odor control chemicals applied to feedlot surfaces have not been demonstrated to be effective in reducing odors from feedlots in humid areas, such as Michigan. In spite of good facilities design and management, odors may be generated from outside livestock lot systems. The intensity of these odors is somewhat proportional to the surface area of the odor producing sources. The frequency of impact and offensiveness to neighbors is often related to the distance to neighbors' houses and their location relative to prevailing winds. 16. New outside lot systems should not be located in close proximity to residences and other odor-sensitive land uses. They should not be located uphill along a confining valley leading toward residences. New residences or other sensitive land uses should not be located within 14

18 close proximity to existing outside lot facilities. (For additional guidance see the GAAMPs for Site Selection and Odor Control for New and Expanding Livestock Production Facilities). Storages and Acceptable Covers 17. Use covered manure storage if technically and economically feasible. 18. Where possible, do not locate manure storage in close proximity to residential areas. The primary objective of storage is to temporarily store the manure before application to land. However, some biological activity occurs in these storages, and the gases generated can be a source of odors. If storage facilities are left uncovered, the potential for manure odors to be carried away by air movement will increase. Various types of covers can be used to prevent wind driven air from coming into direct contact with a liquid manure surface and incorporating odors. Acceptable covers that can retard odor escape from manure storages include the following: a) Natural fibrous mats similar to those which develop on liquid manure storages receiving manure from beef and dairy cattle fed a high roughage diet. b) Slotted flooring or other underbuilding tanks. Ventilation must be provided in the building to prevent accumulation of noxious and flammable gases. c) A flexible plastic or similar material that covers the liquid surface and is of such strength, anchorage and design that the covering will not tear or pull loose when subjected to normal winds that have an average recurrence interval of 25 years. Gas escape ports should be provided which allow any gas that may evolve to escape. d) A solid covering such as concrete, wood, plastic or similar materials that covers the entire liquid surface and is of such strength, anchorage and design that it will withstand winds and expected vertical loads. Adequate air exchange should be provided which will prevent the occurrence of explosive concentrations of flammable gases. Treatment Systems A biological treatment system is designed to convert organic matter (feed, bedding, animal manure, and other by-products) to more stable end products. Anaerobic processes (i.e., without free oxygen) can liquefy or degrade high BOD (biochemical oxygen demand) wastes. They can decompose more organic matter per unit volume than aerobic treatment processes. Aerobic processes require free oxygen and are helpful in reducing odor but are generally not considered economical for livestock operations. Extreme environmental changes alter microbial activity. When 15

19 microorganisms are stressed by their environment, waste treatment processes can malfunction, and odors may become more intense. Lagoons and Storage Facilities Anaerobic treatment lagoons are generally basins containing diluted manure and are designed to provide degradation of the organic material. Well-designed and managed anaerobic lagoons can be short-term odor sources. The occurrence of purple sulfurfixing bacteria can significantly reduce odors from an anaerobic treatment lagoon. The intensity of odors is usually greatest during the early spring and occasionally in the fall. Aerobic treatment of manure liquids can be accomplished by natural or mechanical aeration. In a naturally-aerated system, such as a facultative oxidation treatment lagoon, an aquatic environment occurs in which photosynthesis from algae and surface aeration from the atmosphere provides an aerobic zone in the upper regions of the treatment lagoon. A transition zone occurs below this aerobic zone that has a limited amount of oxygen. This is the facultative zone where bacteria are present that can live either with or without oxygen. At the bottom, there may be a sludge layer that is anaerobic. The processes that occur in the aerobic zone have a low odor potential, and the odorous compounds that are created in the facultative and anaerobic zones are converted to low odor forms in the aerobic zone. For a naturally aerated system to function properly, design specifications and quantities of manure solids to be treated must be closely followed. An aerobic treatment lagoon should be loaded at a rate no higher than 44 pounds of ultimate BOD/day/acre. The material in the treatment lagoon should be diluted enough to allow light to penetrate three to four feet into the water. The lagoon should be a minimum of four feet deep (or deeper to allow for accumulation of sludge) to prevent rooted vegetation from growing from the bottom of the lagoon. Mechanically-aerated systems can be used to treat animal manures to control odors, decompose organic material, remove nitrogen, conserve nitrogen, or a combination of these functions. When adequate oxygen is supplied, a community of aerobic bacteria grows that produce materials with low odor potential. Alternative treatment systems to accomplish mechanical aeration include facultative lagoons, oxidation ditches, or completely mixed lagoons. Storage facilities are designed for manure storage only with no manure treatment. Treatment lagoons (aerobic and anaerobic) are designed specifically for manure treatment. Effluent from treatment lagoons and storage basins should be land applied to avoid long-term and extensive ponding and to utilize manure nutrients at agronomic rates (see Section V). Construction design for treatment lagoons and storage basins should conform to the recommendations in Section IV. 16

20 Composting Composting is a self-heating process carried on by bacteria, actinomycetes and fungi that decompose organic material in the presence of oxygen. Composting of organic material, including livestock manures, can result in a rather stable end product that does not support extensive microbial or insect activity, if the process and systems are properly designed and managed. The potential for odors during the composting process depends upon the moisture content of the organic material, the carbon-nitrogen ratio, the presence of adequate nutrients, the absence of toxic levels of materials that can limit microbial growth, and adequate porosity to allow diffusion of oxygen into the organic material for aerobic decomposition of the organic material. Stability of the end product and its potential to produce nuisance odors, and/or to be a breeding area for flies, depends upon the degree of organic material decomposition and the final moisture content. Additional information and guidance about alternatives for composting manures are available in the "On-Farm Composting Handbook" (Rynk, 1992) and the National Engineering Handbook (USDA, 2000). The occurrence of leachate from the composting material can be minimized by controlling the initial moisture content of the composting mixture to less than 70% and controlling water additions to the composting material from rainfall. Either a fleece blanket 1 or a roofed structure can be used as a cover to control rainfall additions or leachate from composting windrows. Provisions should be made to control and/or treat leachate and runoff to protect groundwater and surface water. If the composting process is conducted without a cover, provisions must be made to collect the surface runoff and it either be temporarily stored (see Section IV) and applied to land (see Section V), added to the composting material for moisture control during the composting process, or applied to grassed infiltration areas (see Section II). Methane Digestors Methane can be produced from animal wastes by anaerobic digestion. This process converts the biodegradable organic portion of animal wastes into biogas (a combination of methane and carbon dioxide). The remaining semi-solid is relatively odor free but still contains all the nitrogen, phosphorus, and potassium originally present in the animal manure, although some of the nitrogen can be lost after storage in a holding pond. Anaerobic digestion is a stable and reliable process, as long as the digester is loaded daily with a uniform quantity of waste, digester temperature does not fluctuate widely, and antibiotics in the waste do not slow biological activity. 1 A fleece blanket is a non-woven textile material made from synthetic fibers, such as polypropylene. The non-woven texture of a fleece blanket prevents rainfall from penetrating into the composting material, but allows the necessary exchange of carbon dioxide and oxygen. 17

21 Application of Manure to Land Manure applications can and should be managed to avoid and minimize nuisance odor conditions that may be experienced by neighbors. Livestock and poultry manure applied to cropland at agronomic rates followed by timely soil incorporation, where feasible, helps to control excessive odors. The following list of practices may be used to reduce odor in the application of manure to land. Appropriate implementation will help reduce complaints of odors. 19. Avoid spreading when the wind is blowing toward populated areas. 20. Avoid spreading on weekends/holidays when people are likely to be engaged in nearby outdoor and recreational activities. 21. Spread in the morning when air begins to warm and is rising, rather than in late afternoon. 22. Use available weather information to best advantage. Turbulent breezes will dissipate and dilute odors, while hot and humid weather tends to concentrate and intensify odors, particularly in the absence of breezes. 23. Take advantage of natural vegetation barriers, such as woodlots or windbreaks, to help filter and dissipate odors. 24. Establish vegetated air filters by planting conifers and shrubs as windbreaks and visual screens between cropland and residential developments. 25. Incorporate manure into soil during, or as soon as possible after, application. This can be done by (a) soil injection or (b) incorporation within 48 hours after a surface application when weather conditions permit. However, incorporation may not be feasible where manures are applied to pastures or forage crops, (see Section V) or where crop residues are retained for erosion control. Incorporation means the physical mixing or movement of surface applied manures and other organic byproducts into the soil so that a significant amount of the material is not present on the soil surface. The physical mixing can be done by using minimal disturbance tillage equipment such as aeration tools. Incorporation also means the soaking of liquid material being applied with irrigation water, barnyard manure runoff, liquid manure, silage leachate, milk house wash water, or liquids from a manure treatment process that separates liquids from solids into the surface soil layer by infiltration, thereby moving surface applied liquid into soils that have void air space not completely filled by soil water. Irrigation of manure to land can be an effective land application method for delivering manure to land in a short period of time without the potential damage to soil structure that can occur with other methods. However, the process can be odorous for a short period of time. 18

22 Land application of liquid manure through an irrigation system is an acceptable method. Three methods are commonly used: Center pivot spray, center pivot with drop tubes, and volume guns either stationary or movable. Center pivots offer excellent uniformity of application, minimize compaction, and allow for timely application. Except for pivots with drop tubes, all the irrigation systems have potential for odor release. If liquid manure is applied through an irrigation system, care should be taken to assure that runoff does not occur due to application rates exceeding the soil infiltration rates. On fractured soils or those with preferential flow paths, care must be taken to assure that manure does not flow into subsurface drains. On systems where the manure is diluted with well or surface water, a check valve assembly must be installed to prevent back flow of manure into the well or surface water source. Spray irrigation produces aerosol sprays that can be detected for long distances. Wind direction and impact on neighbors need to be observed closely. An alternative to traveling big guns that reduces odor is a boom fitted with drop tubes to place the manure below the plant canopy on the soil surface. Research in Europe has shown this method to be effective in minimizing odors. IV. - CONSTRUCTION DESIGN AND MANAGEMENT FOR MANURE STORAGE AND TREATMENT FACILITIES Construction Design 26. Construction design for manure storage and treatment facilities should meet specifications and guidelines found in the NRCS-FOTG. Additional publications that can be used are the Concrete Manure Storages Handbook MWPS-36 (MidWest Plan Service, 1994) and Circular Concrete Manure Tanks publication TR-9 (MidWest Plan Service 1998). Seepage Control for Earthen Basins 27. To protect groundwater from possible contamination, utilize liners that meet specifications and guidelines in the NRCS-FOTG (313 Waste Storage Facility). Liners include natural existing soil (Barrington and Jutras, 1985; Barrington et al., 1987a, 1987b), bentonite or similar high swell clay materials, compacted earthen liners, and flexible membranes. 19

23 Management 28. All manure storage structures shall maintain a minimum freeboard of twelve inches (six inches for fabricated structures) plus the additional storage volume necessary to contain the precipitation and runoff from a 25-year, 24-hour storm event. When considering total storage volume, include all bedding, storm runoff water, milk house and parlor wastewater, and silage leachate that enter the storage structure. In addition, manure storage structure integrity should also be maintained by means of periodic inspections. During these inspections, identify any item that would minimize integrity, such as animal burrows, trees and shrubs growing on the berm, and low areas in the structure that may be conducive to leakage. V. - MANURE APPLICATION TO LAND One of the best uses of animal manure is as a fertilizer for crop production. Recycling plant nutrients from the crop to animals and back to the soil for growth of crops again is an age-old tradition. Depending on the species of animal, 70-80% of the nitrogen (N), 60-85% of the phosphorus (P), and 80-90% of the potassium (K) fed to the animals as feed will be excreted in the manure and potentially available for recycling to soils. Livestock operations can generate large amounts of manure and increase the challenge of recycling manure nutrients for crop production. Good management is the key to ensure that the emphasis is on manure utilization rather than on waste disposal. Utilizing manure nutrients to supply the needs of crops and avoiding excessive loadings achieves two desirable goals. First, efficient use of manure nutrients for crop production will accrue economic benefits by reducing the amounts of commercial fertilizers needed. Second, water quality concerns for potential contamination of surface waters and groundwater by nutrients, microorganisms and other substances from manure can best be addressed when nutrients are applied at agronomic rates and all GAAMPs for manure applications are followed. Application of animal manure to fields used for crop production is the predominant form of manure recycling. Three overriding criteria that need to be considered for every manure application are environmental protection, neighbor relations, and nutrient utilization. The manure should be managed in a manner to retain the nutrients in the soil-plant system. The rate and method of application are influenced by soil and weather conditions. For liquid manure, the receiving soil needs to have enough air space for timely infiltration. All manure applications need to be managed to control odors and prevent runoff from the cropland where the manure is applied. Nutrient utilization management includes the use of current soil test results, manure nutrient analysis or book values, and realistic yield goals. Manure applications may provide 20